As is well known to those skilled in the art, compressed air systems, by virtue of condensation, are subject to moisture, which may cause valves and other mechanical devices in the system to rust. It is absolutely essential, therefore, that as much of the moisture as possible be removed from the compressed air before it is supplied to the devices utilizing this air. For this purpose, a dehumidifier is interposed in the air pressure circuit between the air compressor and the storage reservoir. The dehumidifier contains a desiccant material which, under normal circumstances, obstructs ventilation to a degree and becomes less efficient as moisture increases. Moreover, oil presence in the compressed air also causes deterioration and ineffectiveness of the desiccant. For this reason, dehumidifier systems have been provided with separators, the purpose of which is to remove moisture and foreign matter before the compressed air reaches the dehumidifier. With the addition of the separators, however, certain complexities arise concerning machinery and pipe distribution, because in some instances the separator is disposed in a removed position from the dehumidifier and is, therefore, less effective.